xref: /onnv-gate/usr/src/lib/libc/port/gen/tfind.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
28*0Sstevel@tonic-gate 
29*0Sstevel@tonic-gate /*	Copyright (c) 1988 AT&T	*/
30*0Sstevel@tonic-gate /*	  All Rights Reserved  	*/
31*0Sstevel@tonic-gate 
32*0Sstevel@tonic-gate 
33*0Sstevel@tonic-gate /*
34*0Sstevel@tonic-gate  * Tree search algorithm, generalized from Knuth (6.2.2) Algorithm T.
35*0Sstevel@tonic-gate  *
36*0Sstevel@tonic-gate  * The NODE * arguments are declared in the lint files as char *,
37*0Sstevel@tonic-gate  * because the definition of NODE isn't available to the user.
38*0Sstevel@tonic-gate  */
39*0Sstevel@tonic-gate 
40*0Sstevel@tonic-gate #pragma weak tfind = _tfind
41*0Sstevel@tonic-gate 
42*0Sstevel@tonic-gate #include "synonyms.h"
43*0Sstevel@tonic-gate #include <mtlib.h>
44*0Sstevel@tonic-gate #include <sys/types.h>
45*0Sstevel@tonic-gate #include <search.h>
46*0Sstevel@tonic-gate #include <thread.h>
47*0Sstevel@tonic-gate #include <synch.h>
48*0Sstevel@tonic-gate 
49*0Sstevel@tonic-gate typedef struct node { void *key; struct node *llink, *rlink; } NODE;
50*0Sstevel@tonic-gate 
51*0Sstevel@tonic-gate 
52*0Sstevel@tonic-gate /*	tfind - find a node, or return 0	*/
53*0Sstevel@tonic-gate /*
54*0Sstevel@tonic-gate  * ky is Key to be located
55*0Sstevel@tonic-gate  * rtp is the Address of the root of the tree
56*0Sstevel@tonic-gate  * compar is the Comparison function
57*0Sstevel@tonic-gate  */
58*0Sstevel@tonic-gate void *
59*0Sstevel@tonic-gate tfind(const void *ky, void *const *rtp,
60*0Sstevel@tonic-gate     int (*compar)(const void *, const void *))
61*0Sstevel@tonic-gate {
62*0Sstevel@tonic-gate 	void *key = (char *)ky;
63*0Sstevel@tonic-gate 	NODE **rootp = (NODE **)rtp;
64*0Sstevel@tonic-gate 	if (rootp == NULL)
65*0Sstevel@tonic-gate 		return (NULL);
66*0Sstevel@tonic-gate 	while (*rootp != NULL) {			/* T1: */
67*0Sstevel@tonic-gate 		int r = (*compar)(key, (*rootp)->key);	/* T2: */
68*0Sstevel@tonic-gate 		if (r == 0)
69*0Sstevel@tonic-gate 			return ((void *)*rootp);	/* Key found */
70*0Sstevel@tonic-gate 		rootp = (r < 0) ?
71*0Sstevel@tonic-gate 		    &(*rootp)->llink :		/* T3: Take left branch */
72*0Sstevel@tonic-gate 		    &(*rootp)->rlink;		/* T4: Take right branch */
73*0Sstevel@tonic-gate 	}
74*0Sstevel@tonic-gate 	return (NULL);
75*0Sstevel@tonic-gate }
76